The present invention relates to a water-absorbent structure for various articles requiring a water-absorbing property such as a disposable diaper, a sanitary napkin and disposable wipes and also to a process for making the same.
U.S. Pat. No. 4,500,315 discloses a disposable superthin water-absorbent article. This article comprises a first layer, a second layer and an intermediate layer disposed between these first and second layers. The first layer comprises, in turn, a synthetic fibrous web and a plurality of super-absorbent polymer particles distributed in this web. The second layer is a wad formed by intertwined cellulose fibers or the like contributing to a liquid diffusibility. The intermediate layer also is formed by intertwined cellulose fibers or the like partially contacting with the polymer particles of the first layer. This article is compressed in its thickness direction so as to have a thickness less than half of the thickness before compressed and restores a thickness corresponding to at least 75% of its initial thickness before compressed as the article absorbs liquid such as bodily discharges.
Japanese Patent Application Publication No. 1990-74254A discloses an absorbent pad used in the absorbent article. This absorbent pad comprises a mixture of heat-weldable crimped fibers, fluff pulp and water-absorbent polymer particles. The crimped fibers are heat-welded together to form three-dimensional web formation presenting a mat-like appearance. The absorbent pad is obtained by compressing the fluff pulp and polymer particles in a wetted state together with the crimped fibers and then drying the assembly. The absorbent pad is free from a state of compression as the fluff pulp and the polymer particles absorb water sufficiently to become soft and thereupon the absorbent pad restores its initial mat-like state. After restoration of the initial mat-like state, the crimped fibers become easily deformable and, in consequence, the absorbent pad acquires a compressive elasticity.
In both the article disclosed in U.S. Pat. No. 4,500,315 and the absorbent pad disclosed in Japanese Patent Application Publication, the polymer particles are filled and held in interstices of the fibers. If it is desired to avoid falling off of the polymer particles from the absorbent article or pad, the fiber interstices must be as narrow as possible. As a result, the fiber interstices are choked up as the polymer particles absorb water and swell and a breathability of the absorbent article or pad may be remarkably deteriorated.